Abstract: Rock simulation is the core of the researches such as geotechnical engineering model test and geological core simulation tests. At present, however, the molding simulation results based on artificial materials are greatly different with that from the actual rock properties due to the limitations of existing similarity theory and technical approaches, especially for the molding simulation of soft rock. In this study, the natural red bed is taken as the raw materials and the traditional diagenesis simulation system is improved. The influences of temperature, pore fluid pressure and overlying pressure are considered herein. The formation process of red bed is realized from the loose rock and soil particles to the rock and the engineering standard size soft rock cores are obtained. Based on the comparison results of diagenesis process, physical properties, chemical properties and mechanical properties between the natural red bed soft rock and the soft rock core that based on natural red bed materials, it is found that the simulated soft rock cores have similar properties with that of the natural red beds soft rock. This study break through the limitations where only certain properties can be generally satisfied from the artificial material similarity simulation, 3D printing or other methods. This study can provide a new manufacturing ideas and methods for the research of large demand soft rock core with differing functional requirements.

Key words: natural red beds material, soft rock, molding simulation, standard size rock core, diagenesis process